Cryogenic kyphoplasty instrument and methods of use

ABSTRACT

A surgical instrument includes an outer shaft defining a passageway. An inner shaft is disposed within the passageway and defines a lumen. An expandable structure has a first end coupled to a second end of the outer shaft and a second end coupled to a second end of the inner shaft. The expandable member defines a chamber. A delivery shaft includes a first end positioned within the passageway and a second end positioned within the chamber. The delivery shaft defines a channel configured to deliver a coolant out of an opening in the second end of the delivery shaft and into the chamber to move the expandable structure from an unexpanded configuration to an expanded configuration. A variable exhaust valve is in communication with the passageway and is configured to regulate pressure within the chamber. Systems and methods are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application U.S. patentapplication Ser. No. 14/288,437, filed on May 28, 2014, now U.S. Pat.No. 9,936,997, which is hereby incorporated by reference herein, in itsentirety.

TECHNICAL FIELD

The present disclosure generally relates to medical devices for thetreatment of musculoskeletal disorders, and more particularly to asurgical system and method to facilitate treatment while minimizingpain.

BACKGROUND

Spinal disorders such as degenerative disc disease, disc herniation,osteoporosis, spondylolisthesis, stenosis, scoliosis and other curvatureabnormalities, kyphosis, tumor, and fracture may result from factorsincluding trauma, disease and degenerative conditions caused by injuryand aging. Spinal disorders typically result in symptoms including pain,nerve damage, and partial or complete loss of mobility.

In an effort to more effectively and directly treat vertebralcompression fractures, minimally invasive techniques such asvertebroplasty and, subsequently, kyphoplasty, have been developed.Vertebroplasty involves creating a cavity in a fractured, weakened, ordiseased vertebral body. A flowable reinforcing material, usuallypolymethylmethacrylate (PMMA—commonly known as bone cement), is injectedinto the cavity. Shortly after injection, the liquid filling materialhardens or polymerizes, desirably supporting the vertebral bodyinternally, alleviating pain and preventing further collapse of theinjected vertebral body. However, creating the cavity in the fractured,weakened, or diseased vertebral body may involve pain, if untreated.

Traditional cryogenic systems, such as, for example, cryoablationsystems can provide denervation capabilities, but the procedures cantake a considerable amount of time to perform. Another problem withcurrently available cryoablation devices is that they are not costeffective. Further, the health care practitioner may have difficultypositioning the tip of the device in the optimal location to get anoptimal and consistent clinical result. This may also result in unwantednecrosis of adjacent tissue, which can lead to clinical adverse eventsincluding subsequent repair of the necrotic tissue. This disclosuredescribes an improvement over these prior art technologies.

SUMMARY

In one embodiment, a surgical instrument is provided. The surgicalinstrument comprises an outer shaft extending along a longitudinal axisbetween a first end and an opposite second end. The outer shaftcomprises an inner surface defining a passageway. An inner shaft isdisposed within the passageway. The inner shaft extends between a firstend and an opposite second end. The inner shaft comprises an innersurface defining a lumen. An expandable structure has a first endcoupled to the second end of the outer shaft and an opposite second endcoupled to the second end of the inner shaft. The expandable membercomprises an inner surface defining a chamber. A delivery shaftcomprises a first end positioned within the passageway and a second endpositioned within the chamber. The delivery shaft comprises an innersurface defining a channel configured to deliver a coolant out of anopening in the second end of the delivery shaft and into the chamber tomove the expandable structure from an unexpanded configuration to anexpanded configuration. A variable exhaust valve is in communicationwith the passageway and is configured to regulate pressure within thechamber. In some embodiments, systems and methods are provided.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more readily apparent from thespecific description accompanied by the following drawings, in which:

FIG. 1 is a side, cross sectional view of components of one embodimentof a surgical system in accordance with the principles of the presentdisclosure;

FIG. 2 is a cross sectional view of components shown in FIG. 1, taken atDetail A in FIG. 1;

FIG. 3 is a cross sectional view of components shown in FIG. 1 takenalong lines B-B in FIG. 2;

FIG. 4 is a plan view of components shown in FIG. 1, used in connectionwith a surgical procedure;

FIG. 5 is a plan view of components shown in FIG. 1, used in connectionwith a surgical procedure;

FIG. 6 is a plan view of components shown in FIG. 1, used in connectionwith a surgical procedure;

FIG. 7 is a plan view of components shown in FIG. 1, used in connectionwith a surgical procedure;

FIG. 8 is a plan view of components shown in FIG. 1, used in connectionwith a surgical procedure; and

FIG. 9 is a plan view of components shown in FIG. 1, used in connectionwith a surgical procedure.

DETAILED DESCRIPTION

The exemplary embodiments of a surgical system and related methods ofuse disclosed are discussed in terms of medical devices for thetreatment of musculoskeletal disorders and more particularly, in termsof a surgical system and method to facilitate treatment while minimizingpain. In one embodiment, the surgical system includes a surgicalinstrument that reduces pain associated with a surgical procedure, suchas, for example, a kyphoplasty procedure. In some embodiments, theinstrument includes a Cryo balloon that is filled and/or inflated usinga coolant, such as, for example nitrous oxide (N₂O). In someembodiments, the instrument is configured to deform tissue, such as, forexample, create a cavity in cancellous bone. Cryo energy is delivered tosurrounding tissue to lessen pain associated with the procedure. In someembodiments, the Cryo energy is delivered at the same time the cavity iscreated. Once the Cryo energy denervates surrounding nerves, the cavityis filled with a material, such as, for example, bone cement. In someembodiments, one balloon is used to create the cavity. The balloon isremoved and another balloon is inserted into the cavity that emits Cryoenergy to nerves surrounding the balloon. Once the Cryo energydenervates surrounding nerves, the cavity is filled with a material,such as, for example, bone cement. In some embodiments, denervation haspain benefits to the overall spinal pain. In some embodiments,denervation decreases pain associated with the procedure. In someembodiments, denervation slows the progression of the compressions.

In some embodiments, a narrow pathway is made into fractured bone usinga hollow instrument. A small orthopaedic balloon is guided through theinstrument into the vertebral body. In some embodiments, the incisionsite is approximately 1 cm (⅓ inch) in length. In some embodiments, twoballoons are used, one on each side of the vertebral body, to bettersupport the bone as it moves back into position and increase thelikelihood of deformity correction. In some embodiments, the instrumentincludes a balloon capable of very high internal pressures, such as, forexample, pressures equal to or greater than about 400 psi. These highpressures are required to form a cavity in bone. The cavity providesspace for bone cement. The balloons are carefully inflated in an attemptto raise the collapsed vertebral body and return it to its normalposition. In some embodiment, a coolant such as, for example, nitrousoxide is used to fill at least one of the balloons. In some embodiments,the coolant is delivered into the balloon as a liquid. Once it entersthe balloon, the liquid goes from an area of high pressure (inside thecoolant lumen) to low pressure (in the balloon chamber). This pressuregradient cause the liquid to evaporate to a gas, thus inflating theballoon. The larger the pressure drop, the colder the temperature. Theballoon pressure can be controlled by a pressure regulator and also theballoon outer diameter can be controlled by the balloon pressure.Inflation of the balloons creates a cavity (space) within the vertebralbody that compacts the soft, inner bone against the outer wall. Thecavity also functions as a “container” for tile bone cement. Once thevertebral body is in the correct position, the balloons are deflated andremoved. In some embodiments, the pressure within the balloons isreduced prior to deflating and/or removing the balloons. In someembodiments, the pressure within the balloons is reduced via a variableexhaust valve. As the nitrous oxide transitions from a liquid to a gas,the nitrous oxide creates cold energy that denervates surroundingnerves. Following denervation, the balloon(s) is/are removed and thecavity is filled with thick bone cement to stabilize the fracture. Thebone cement forms an internal cast that holds the vertebral body inplace.

In some embodiments, the instrument includes a balloon capable of veryhigh internal pressures, such as, for example, pressures equal to orgreater than about 400 psi. In some embodiments, the instrument includesa balloon capable of very high internal pressures, such as, for example,pressures equal to or greater than about 700 psi. This allows nitrousoxide to be delivered into the balloon under significant pressure suchthat the balloon creates a cavity in bone. Pressure within the balloonis decreased via a variable exhaust valve. In some embodiments, thepressure is reduced to between about 5 and about 25 psi to create coldenergy that denervates nerves surrounding the balloon. In someembodiments, the balloon is a single wall balloon to allow for efficientenergy transfer of the cold energy created by the pressure reductionwithin the balloon on the nitrous oxide. In some embodiments, thenitrous oxide transitions from a liquid to a gas as a result of thepressure reduction within the balloon. In some embodiments, exhaust gasis provisionally stored in a handle of the instrument, but does not exitthe system until it reaches a threshold set by the system. In someembodiments, the threshold is high for kyphoplasty and is low fordenervation. In some embodiments, the instrument includes a controlsystem that can toggle between high and low pressure to create a cavityand then denervate the nerves. In some embodiments, the entire systemcan be controlled by a console. In some embodiments, the entire systemcan be controlled by a smart handle. In some embodiments, feedback ontemperatures and balloon pressure is monitored for controlledkyphoplasty/denervation.

In some embodiments, the balloon can be inflated incrementally withpressure to control the balloon outer diameter and thus control thecreation of the cavity. This can start at a low pressure of about 50 psiand rise gradually to about 400 psi. In some embodiments, the balloon isinflated to have an internal pressure of about 50 psi to create a cavitywithin bone and the pressure within the balloon is reduced to about 10psi to cause the nitrous oxide to transition from liquid to gas tocreate cold energy to denervate nerves within the bone. In someembodiments, the balloon is inflated to have an internal pressure ofabout 100 psi to create a cavity within bone and the pressure within theballoon is reduced to about 10 psi to cause the nitrous oxide totransition from liquid to gas to create cold energy to denervate nerveswithin the bone. In some embodiments, the balloon is inflated to have aninternal pressure of about 150 psi to create a cavity within bone andthe pressure within the balloon is reduced to about 10 psi to cause thenitrous oxide to transition from liquid to gas to create cold energy todenervate nerves within the bone. In some embodiments, the balloon isinflated to have an internal pressure of about 200 psi to create acavity within bone and the pressure within the balloon is reduced toabout 10 psi to cause the nitrous oxide to transition from liquid to gasto create cold energy to denervate nerves within the bone. In someembodiments, the balloon is inflated to have an internal pressure ofabout 250 psi to create a cavity within bone and the pressure within theballoon is reduced to about 10 psi to cause the nitrous oxide totransition from liquid to gas to create cold energy to denervate nerveswithin the bone. In some embodiments, the balloon is inflated to have aninternal pressure of about 300 psi to create a cavity within bone andthe pressure within the balloon is reduced to about 10 psi to cause thenitrous oxide to transition from liquid to gas to create cold energy todenervate nerves within the bone. In some embodiments, the balloon isinflated to have an internal pressure of about 350 psi to create acavity within bone and the pressure within the balloon is reduced toabout 10 psi to cause the nitrous oxide to transition from liquid to gasto create cold energy to denervate nerves within the bone. In someembodiments, the balloon is inflated to have an internal pressure ofabout 400 psi to create a cavity within bone and the pressure within theballoon is reduced to about 10 psi to cause the nitrous oxide totransition from liquid to gas to create cold energy to denervate nerveswithin the bone.

In some embodiments, the present disclosure may be employed to treatspinal disorders such as, for example, degenerative disc disease, discherniation, osteoporosis, spondylolisthesis, stenosis, scoliosis andother curvature abnormalities, kyphosis, tumor and fractures. In someembodiments, the present disclosure may be employed with other ostealand bone related applications, including those associated withdiagnostics and therapeutics. In some embodiments, the disclosedsurgical system may be alternatively employed in a surgical treatmentwith a patient in a prone or supine position, and/or employ varioussurgical approaches to the spine, including anterior, posterior,posterior mid-line, lateral, postero-lateral, and/or antero-lateralapproaches, and in other body regions. The present disclosure may alsobe alternatively employed with procedures for treating the lumbar,cervical, thoracic, sacral and pelvic regions of a spinal column. Thesurgical system of the present disclosure may also be used on animals,bone models and other non-living substrates, such as, for example, intraining, testing and demonstration.

The present disclosure may be understood more readily by reference tothe following detailed description of the embodiments taken inconnection with the accompanying drawing figures, which form a part ofthis disclosure. It is to be understood that this application is notlimited to the specific devices, methods, conditions or parametersdescribed and/or shown herein, and that the terminology used herein isfor the purpose of describing particular embodiments by way of exampleonly and is not intended to be limiting. Also, in some embodiments, asused in the specification and including the appended claims, thesingular forms “a,” “an,” and “the” include the plural, and reference toa particular numerical value includes at least that particular value,unless the context clearly dictates otherwise. Ranges may be expressedherein as from “about” or “approximately” one particular value and/or to“about” or “approximately” another particular value. When such a rangeis expressed, another embodiment includes from the one particular valueand/or to the other particular value. Similarly, when values areexpressed as approximations, by use of the antecedent “about,” it willbe understood that the particular value forms another embodiment. It isalso understood that all spatial references, such as, for example,horizontal, vertical, top, upper, lower, bottom, left and right, are forillustrative purposes only and can be varied within the scope of thedisclosure. For example, the references “upper” and “lower” are relativeand used only in the context to the other, and are not necessarily“superior” and “inferior”.

Further, as used in the specification and including the appended claims,“treating” or “treatment” of a disease or condition refers to performinga procedure that may include administering one or more drugs to apatient (human, normal or otherwise or other mammal), employingimplantable devices, and/or employing instruments that treat thedisease, such as, for example, microdiscectomy instruments used toremove portions bulging or herniated discs and/or bone spurs, in aneffort to alleviate signs or symptoms of the disease or condition.Alleviation can occur prior to signs or symptoms of the disease orcondition appearing, as well as after their appearance. Thus, treatingor treatment includes preventing or prevention of disease or undesirablecondition (e.g., preventing the disease from occurring in a patient, whomay be predisposed to the disease but has not yet been diagnosed ashaving it). In addition, treating or treatment does not require completealleviation of signs or symptoms, does not require a cure, andspecifically includes procedures that have only a marginal effect on thepatient. Treatment can include inhibiting the disease, e.g., arrestingits development, or relieving the disease, e.g., causing regression ofthe disease. For example, treatment can include reducing acute orchronic inflammation; alleviating pain and mitigating and inducingre-growth of new ligament, bone and other tissues; as an adjunct insurgery; and/or any repair procedure. Also, as used in the specificationand including the appended claims, the term “tissue” includes softtissue, ligaments, tendons, cartilage and/or bone unless specificallyreferred to otherwise.

The following discussion includes a description of a surgical system andmethods of employing the surgical system in accordance with theprinciples of the present disclosure. Alternate embodiments are alsodisclosed. Reference will now be made in detail to the exemplaryembodiments of the present disclosure, which are illustrated in theaccompanying figures. Turning to FIGS. 1-9, there are illustratedcomponents of a surgical system 10 including a surgical device, such as,for example, a surgical instrument 12 in accordance with the principlesof the present disclosure.

The components of surgical system 10 can be fabricated from biologicallyacceptable materials suitable for medical applications, includingmetals, synthetic polymers, ceramics and bone material and/or theircomposites, depending on the particular application and/or preference ofa medical practitioner. For example, the components of surgical system10, individually or collectively, can be fabricated from materials suchas stainless steel alloys, commercially pure titanium, titanium alloys,Grade 5 titanium, superelastic titanium alloys, cobalt-chrome alloys,stainless steel alloys, superelastic metallic alloys (e.g., Nitinol,super elasto-plastic metals, such as GUM METAL® manufactured by ToyotaMaterial Incorporated of Japan), ceramics and composites thereof such ascalcium phosphate (e.g., SKELITE™ manufactured by Biologix Inc.),thermoplastics such as polyaryletherketone (PAEK) includingpolyetheretherketone (PEEK), polyetherketoneketone (PEKK) andpolyetherketone (PEK), carbon-PEEK composites, PEEK-BaSO₄ polymericrubbers, polyethylene terephthalate (PET), fabric, silicone,polyurethane, silicone-polyurethane copolymers, polymeric rubbers,polyolefin rubbers, hydrogels, semi-rigid and rigid materials,elastomers, rubbers, thermoplastic elastomers, thermoset elastomers,elastomeric composites, rigid polymers including polyphenylene,polyamide, polyimide, polyetherimide, polyethylene, epoxy, bone materialincluding autograft, allograft, xenograft or transgenic cortical and/orcorticocancellous bone, and tissue growth or differentiation factors,partially resorbable materials, such as, for example, composites ofmetals and calcium-based ceramics, composites of PEEK and calcium basedceramics, composites of PEEK with resorbable polymers, totallyresorbable materials, such as, for example, calcium based ceramics suchas calcium phosphate, tri-calcium phosphate (TCP), hydroxyapatite(HA)-TCP, calcium sulfate, or other resorbable polymers such aspolyaetide, polyglycolide, polytyrosine carbonate, polycaroplaetohe andtheir combinations. Various components of surgical system 10 may havematerial composites, including the above materials, to achieve variousdesired characteristics such as strength, rigidity, elasticity,compliance, biomechanical performance, durability and radiolucency orimaging preference. The components of surgical system 10, individuallyor collectively, may also be fabricated from a heterogeneous materialsuch as a combination of two or more of the above-described materials.The components of surgical system 10 may be monolithically formed,integrally connected or include fastening elements and/or instruments,as described herein.

Instrument 12 comprises an outer shaft 14 extending along a longitudinalaxis C between an end 16 and an opposite end 18. Shaft 14 has a lengthdefined by the distance between ends 16, 18. In some embodiments, shaft14 has a uniform width and/or diameter along the entire length of shaft14. Shaft 14 comprises an inner surface 20 defining a passageway 22having a cylindrical cross sectional configuration. End 18 comprises acircular opening 24 that is in communication with passageway 22. Opening24 is coaxial with axis C. Passageway 22 has a length defined by thelength of shaft 14. In some embodiments, passageway 22 has a uniformwidth and/or diameter along the entire length of passageway 22. In someembodiments, shaft 14 comprises a flexible material such that shaft 14can bend without breaking. In some embodiments, shaft 14 comprises arigid material such that shaft 14 cannot bend without breaking. In someembodiments, at least a portion of shaft 14 is transparent ortranslucent to permit visualization of components within passageway 22.In some embodiments, passageway 22 and/or opening 24 may have variouscross section configurations, such as, for example, oval, oblong,triangular, rectangular, square, polygonal, irregular, uniform,non-uniform, variable, tubular and/or tapered. In some embodiments,opening 24 may be disposed at alternate orientations, relative to axisC, such as, for example, transverse, perpendicular and/or other angularorientations such as acute or obtuse, co-axial and/or may be offset orstaggered.

An inner shaft 26 is disposed within passageway 22 such that shaft 26 iscoaxial with axis C. Shaft 26 extends between an end 28 and an oppositeend 30. Shaft 26 has a length defined by the distance between ends 28,30. In some embodiments, shaft 26 has a uniform width and/or diameteralong the entire length of shaft 26. Shaft 26 comprises an inner surface32 defining a lumen 34 having a cylindrical cross sectionalconfiguration. Lumen 34 has a length defined by the length of shaft 26.In some embodiments, lumen 34 has a uniform width and/or diameter alongthe entire length of lumen 34. In some embodiments, shaft 26 comprises aflexible material such that shaft 26 can bend without breaking. In someembodiments, shaft 26 comprises a rigid material such that shaft 26cannot bend without breaking. In some embodiments, at least a portion ofshaft 26 is transparent or translucent to permit visualization ofcomponents within lumen 34. In some embodiments, end 28 includes acircular aperture 36 an end 30 comprises a circular aperture 38.Apertures 36, 38 are in communication with lumen 34 such that acomponent, such as, for example, a guide wire can be inserted intoaperture 36 and be positioned such that an end of the guide wire extendsthrough aperture 38. Apertures 36, 38 are each coaxial with axis C. Insome embodiments, end 30 comprises an end surface extendingperpendicular to axis C such that end 30 is closed. In some embodiments,lumen 34, aperture 36 and/or aperture 38 may have various cross sectionconfigurations, such as, for example, oval, oblong, triangular,rectangular, square, polygonal, irregular, uniform, non-uniform,variable, tubular and/or tapered. In some embodiments, lumen 34,aperture 36 and/or aperture 38 may be disposed at alternateorientations, relative to axis C, such as, for example, transverse,perpendicular and/or other angular orientations such as acute or obtuse,co-axial and/or may be offset or staggered. In some embodiments, shaft26 is rotatably and/or slidably disposed within passageway 26. In someembodiments, shaft 26 is fixed relative to shaft 14. For example, in oneembodiment, end 28 extends through an opening 54 in end 16 and is fixedto a handle 55. End 16 is also fixed to handle 55 to fix shaft 26relative to shaft 14. In some embodiments, handle 55 is an ergonomichandle configured to be gripped by hand by a medical practitioner.

An expandable structure, such as, for example, a balloon 40 comprises anend 42 coupled to end 18 such that an inner surface 44 of balloon 40engages an outer surface of shaft 14 and an opposite end 44 coupled toend 30 such that surface 44 engages an outer surface of shaft 26. Insome embodiments, balloon 40 is attached to shafts 14, 26 by adhesivebonding, thermal bonding, laser bonding, or RF bonding. Surface 44defines a chamber 48 configured for disposal of a material to increasepressure within chamber 48 to move balloon 40 from an unexpanded orcollapsed orientation, as shown in FIG. 4, to an expanded or inflatedorientation, as shown in FIG. 5. In some embodiments, balloon 40 is asingle wall balloon made from a compliant material. In some embodiments,balloon 40 comprises a thin, single layer of material configured topermit the transfer of energy, such as, for example, cold and/or Cryoenergy through the balloon wall. In some embodiments, a tip of shaft 26extends beyond end 46, as shown in FIG. 1. In some embodiments, the tipof shaft is flush with end 46, as shown in FIG. 2. In some embodiments,balloon 40 comprises various compliant and/or non-compliant materials,for example, latex and/or polyethylene terephthalate (PET),polyurethane, nylon or polyether block amide. Other materials are alsocontemplated. In some embodiments, at least a portion of balloon 40comprises a transparent or translucent material to facilitatevisualization of components disposed within chamber 48. In someembodiments, the shapes and sizes of balloon 40 when in the expandedorientation can be selected to provide a desired result during aprocedure. For example, balloon 40 may include shapes such as spheres,cylinders, multi-lobed shapes, etc. and have different dimensions tomake balloon 40 narrower or wider in a longitudinal direction, or extendfurther in a radial direction, etc.

Chamber 48 is configured to transition between a deflated or collapsedorientation and an inflated or expanded orientation, as discussed above.Chamber 48 is shown in the expanded orientation in FIGS. 1-3, 5 and 6.Chamber 48 is shown in the collapsed orientation in FIG. 4. To movechamber 48 from the collapsed orientation to the expanded orientation, amaterial source, such as, for example, a coolant source 50, is coupledto instrument 12. Source 50 includes a delivery shaft 51 comprising aninner surface defining a channel, such as, for example, an inlet 52. Anend of shaft 51 is directly coupled to source 50 and an opposite end 56of shaft 51 is positioned in chamber 48. An intermediate portion ofshaft 51 is positioned in passageway 22. End 56 includes an opening 58that is in communication with inlet 52 such that a material can bedelivered from source 50, through inlet 52 and exit inlet 52 throughopening 58 for disposal in chamber 48. As the material is introducedinto chamber 48, pressure within chamber 48 increases, causing chamber48 to transition from the collapsed orientation to the expandedorientation. Shaft 51 and opening 58 each extend parallel to axis C andare offset from axis C. In some embodiments, shaft 51 is directlycoupled to the outer surface of shaft 26 such that shaft 51 is fixed toshaft 26 and/or shaft 51 extends parallel to axis C. In someembodiments, shaft 51 is removable from shaft 26 and/or is movablerelative to shaft 26. In some embodiments, source 50 comprises a heatelement 60 comprising at least one heating and/or cooling element, suchas, for example, a thermoelectric device configured to heat and/or coolthe material stored within source 50 to adjust the temperature of thematerial, as selected by a medical practitioner, for example. In someembodiments, the material stored within source 50 is pressurized. Insome embodiments, the material stored within source 50 comprises apressure of at least about 50 psi. In some embodiments, the materialstored within source 50 comprises a pressure of at least about 100 psi.In some embodiments, the material stored within source 50 comprises apressure of at least about 400 psi. In some embodiments, the materialstored within source 50 comprises a pressure of at least about 700 psi.In some embodiments, the material stored within source 50 comprises acoolant or refrigerant, such as, for example, nitrous oxide (N₂O). Insome embodiments, the nitrous oxide is stored within source 50 as aliquid. In some embodiments, the material stored within source 50comprises other cryogens and/or liquefied gases, such as, for example,liquid nitrogen and/or liquid helium.

Instrument 12 includes a pressure monitor 62 positioned outside ofpassageway 26 such that pressure monitor 62 is accessible and/orviewable by a medical practitioner. Pressure monitor 62 comprises aconduit 64 comprising an end 66 that extends through handle 55 and ispositioned in passageway 26 and an opposite end 68 positioned withinchamber 48. In some embodiments, conduit 64 is directly coupled shaft 26such that an outer surface of conduit 64 engages the outer surface ofshaft 26 and/or conduit 64 extends parallel to axis C. In someembodiments, conduit 64 is removable from shaft 26 and/or is movablerelative to shaft 26. Conduit 64 comprises an inner surface defining achannel that is in communication with pressure monitor 62. End 68comprises an opening 70 that is in communication with the channeldefined by the inner surface of conduit 64 such that pressure withinchamber 48 can be detected by pressure monitor 62. In some embodiments,pressure monitor 62 includes a display configured to provide avisualization of the pressure within chamber 48. In some embodiments,pressure monitor 62 comprises audio and/or visual components, such as,for example lights or speakers configured to provide alerts whenpressure within chamber 48 reaches and/or exceeds a selected thresholdpressure. For example, a medical practitioner may preset pressuremonitor 62 to provide an alert if and when pressure within chamber 48reaches and/or exceeds 700 psi, for example, to avoid overinflatingballoon 40 and/or rupturing balloon 40. As a further example, a medicalpractitioner may preset pressure monitor 62 to provide an alert if andwhen pressure within chamber 48 reaches and/or drops below 10 psi, forexample, to indicate when pressure within chamber 48 decreases to aselected threshold.

Instrument 12 comprises a variable exhaust valve 72 extending throughhandle 55 such that valve 72 is in communication with passageway 26.Valve 72 is configured to regulate pressure within chamber 48. In someembodiments, valve 72 is in communication with pressure monitor 62.Valve 72 is configured to open when pressure within chamber 48 reaches afirst selected threshold pressure and to close when pressure withinchamber 48 drops to a second selected threshold pressure. For example,valve 72 may be preset to open when pressure within chamber 48 reaches afirst selected threshold pressure, such as, for example, 700 psi. Whenvalve 72 is open, pressure within chamber 48 decreases. Pressure withinchamber 48 decreases to a second selected threshold pressure, such as,for example, 10 psi, thus causing valve 72 to close. When valve 72 isclosed, pressure within chamber 48 remains constant.

In some embodiments, instrument 12 comprises a thermocouple 74 disposedin lumen 34 configured to detect temperature within chamber 48. In someembodiments, thermocouple 74 comprises an end 76 coupled to handle 55and an opposite end 78 positioned in a portion of lumen 34 that ispositioned within chamber 48 such that thermocouple 74 can detecttemperature within chamber 48. In some embodiments, thermocouple 74 iscoaxial with axis C. In some embodiments, thermocouple 74 is removablefrom lumen 34.

In assembly, operation and use, surgical system 10, similar to thatdescribed above, is employed, for example, with a minimally invasivesurgical procedure for spinal and neurosurgical applications with apatient, as shown in FIGS. 4-9. For example, during spine surgery, asurgeon will make an incision in the skin of a patient's back oververtebrae to be treated. One or more hollow instruments, such as, forexample, dilators may be employed to gradually separate the muscles andcreate a portal to a surgical site, such as, for example, a fracturedbone, such as, for example, a fractured and/or collapsed vertebral bodyVB. In some embodiments, the incision is about 1 cm (about ⅓ inch) inlength.

Instrument 12 is positioned adjacent a surgical site over the incision.Instrument 12 is passed through the incision and positioned adjacentvertebral body VB. Instrument 12 is positioned relative to vertebralbody VB such that balloon 40 is positioned within vertebral body VB,with chamber 48 in the collapsed orientation, as shown in FIG. 4. Whenballoon 40 is positioned within vertebral body VB, valve 72 is closedand is preset to open when pressure within chamber 48, as detected bypressure monitor 62, reaches a first selected threshold pressure, suchas, for example, a pressure within a range of about 50 psi to about 700psi. Valve 72 is also preset to close when pressure within chamber, asdetected by pressure monitor 62, drops to a second threshold pressure,such as for example, a pressure within a range of about 5 psi to about15 psi. In some embodiments, a guide wire GW is inserted through opening36 and into lumen 34 such that a tip T of guide wire GW engages tissue,such as, for example, bone, as shown in FIG. 4. Instrument 12 is slidalong guide wire GW to position instrument 12 such that balloon 40 ispositioned within vertebral body VB.

An inflation and/or filler material M, such as, for example, pressurizedliquid nitrous oxide is delivered from source 50 through inlet 52 in thedirection shown by arrow D such that pressurized liquid nitrous oxide Mexits opening 58 for disposal within chamber 48. Pressurized liquidnitrous oxide M continues to be delivered into chamber 48 until pressurewithin chamber 48 reaches the first selected threshold pressure. Aspressure in chamber 48 reaches the first selected threshold pressure,chamber 48 moves from the unexpanded or uninflated orientation shown inFIG. 4 to the expanded or inflated orientation shown in FIG. 5. Aschamber 48 moves from the unexpanded or uninflated orientation to theexpanded or inflated orientation, balloon 40 applies an outward force onvertebral body VB so as to raise vertebral body VB and return it to itsnormal position. As balloon 40 applies an outward force on vertebralbody VB, balloon 40 compacts soft, inner bone against the outer surfaceof balloon 40 so as to create a cavity C1 within vertebral body VB, asshown in FIGS. 5 and 7.

Chamber 48 is filled with pressurized liquid nitrous oxide M untilpressure within chamber 48 reaches the first selected thresholdpressure. When pressure within chamber 48 reaches the first selectedthreshold pressure, valve 72 opens. When valve 72 opens, nitrous oxide Mmoves through passageway 22 in the direction shown by arrow E such thatnitrous oxide M exits instrument 12 through valve 72 to reduce pressurewithin chamber 48. Valve 72 remains open until pressure within chamber48 reaches the second selected threshold pressure. When pressure withinchamber 48 reaches the second selected threshold pressure, valve 72closes, thus preventing nitrous oxide M from exiting instrument 12through valve 72 and maintaining the pressure within chamber 48 at thesecond selected threshold pressure. The pressure difference between thefirst selected threshold pressure and the second selected thresholdpressure causes nitrous oxide M to evaporate, thus producing cold energyCE. Cold energy CE is transmitted through the wall of balloon 40 suchthat cold energy CE acts on nerves within vertebral body VB to denervateand/or otherwise numb the nerves, as shown in FIG. 6.

In some embodiments, source 50 is in communication pressure monitor 62such that when pressure monitor 62 detects that pressure within chamber48 reaches the first selected threshold pressure, pressure monitor 62sends a signal to source 50 causing a pump of source 50 to stop pumpingnitrous oxide M. In some embodiments, source 50 is in communicationpressure monitor 62 via one or more wires that connect source 50 withpressure monitor 62. In some embodiments, source 50 includes a pump thatis turned on and off manually, based upon the pressure within chamber48, as identified by a medical practitioner upon viewing and/or hearingpressure monitor 62. For example, a medical practitioner may turn thepump of source 50 off when he or she identifies that pressure withinchamber 48 reached the first selected threshold pressure to stop thepump from pumping nitrous oxide M into chamber 48. In some embodiments,valve 72 is in communication with pressure monitor 62 such that whenpressure monitor 62 detects that pressure within chamber 48 reaches thefirst selected threshold pressure, pressure monitor 62 sends a signal tovalve 72 causing valve 72 to open. In some embodiments, valve 72 is incommunication with pressure monitor 62 via one or more wires thatconnect pressure monitor 62 with valve 72. Likewise, when pressuremonitor 62 detects that pressure within chamber 48 reaches the secondselected threshold pressure, pressure monitor 62 sends a signal to valve72 causing valve 72 to close. In some embodiments, valve 72 is openedand closed manually when a medical practitioner identifies, via pressuremonitor 62, that pressure within chamber 48 reaches the first selectedthreshold pressure or the second selected threshold pressure.

Once the nerves within vertebral body VB are sufficiently denervatedand/or numbed, valve 72 is opened, causing nitrous oxide M withinchamber 48 to move through passageway 22 in the direction shown by arrowE and exit instrument 12 via valve 72. As nitrous oxide M exitsinstrument 12, chamber 48 returns to the unexpanded or uninflatedorientation shown in FIG. 2. In some embodiments, shaft 26 is slidablydisposed within passageway 22 such that moving shaft 26 axially alongaxis C in the direction shown by arrow E until at least a portion ofballoon 40 is disposed within passageway 22, as shown in FIG. 7.Instrument 12 is removed from vertebral body VB with balloon 40 disposedin passageway 22 to reduce the maximum width and/or diameter ofinstrument 12 to facilitate removal thereof. In some embodiments,instrument 12 is removed without balloon 40 being positioned inpassageway 22.

An instrument, such as, for example, instrument 12 is introduced intothe surgical site and positioned adjacent cavity C1. A material, suchas, for example, bone cement BC is delivered through instrument 12 fordelivery into cavity C1, as shown in FIG. 8. Bone cement BC is deliveredinto cavity C1 until a selected amount of bone cement BC is disposed incavity C1. In some embodiments, bone cement BC is delivered into cavityC1 until bone cement BC completely fills cavity C1, as shown in FIG. 9.After cavity C1 is filled an amount selected by a medical practitioner,instrument 12 is removed from the surgical site, as shown in FIG. 9. Insome embodiments, a source of bone cement BC is coupled to tube 26 suchthat bone cement BC is delivered from the source of bone cement BCthrough lumen 34 and out of opening 38 for disposal in cavity C1. Insome embodiments, the instrument that is used to deliver bone cement BCinto cavity C1 is different from instrument 12. In some embodiments, theinstrument that is used to deliver bone cement BC into cavity C1 is acannula. Upon completion of the surgical procedure, instrument 12 and/orthe instrument that is used to deliver bone cement BC into cavity C1 isremoved from the surgical site.

In some embodiments, system 10 includes at least two instruments 12,which may be used simultaneously in the method discussed above. In oneembodiment, a first instrument 12 is positioned adjacent a first side ofvertebral body VB such that balloon 40 of the first instrument 12 ispositioned within the first side of vertebral body. A second instrument12 is positioned adjacent a second side of vertebral body VB oppositethe first side of vertebral body VB such that balloon 40 of the secondinstrument 12 is positioned within the second side of vertebral body VB.Balloons 40 of the first and second instruments 12 are inflated withpressurized liquid nitrous oxide in the manner discussed above such thatthe first and second instruments 12 each restore the height of arespective side of vertebral body VB. Valves 72 on each of the first andsecond instruments 12 open when pressure within a respective chamber 48reaches a first selected threshold pressure and the first and secondinstruments 12 each create a cavity similar to cavity C1. Valves 72 oneach of the first and second instruments 12 when pressure within arespective chamber 48 drops to a second selected threshold pressure. Asthe pressure within chambers 48 drops to the second selected thresholdpressure, the difference in pressure between the first selectedthreshold pressure and the second selected threshold pressure causesnitrous oxide M to evaporate, thus creating cold energy. Balloons 40and/or the first and second instruments 12 may be removed from vertebralbody VB once nerves in vertebral body VB are sufficiently denervatedand/or numbed. The cavities created by the first and second instruments12 may then be filled with bone cement BC in the manner discussed above.

Instrument 12 may be employed for performing spinal surgeries, such as,for example, laminectomy, discectomy, fusion, laminotomy, nerve rootretraction, foramenotomy, facetectomy, decompression, spinal nucleus ordisc replacement and procedures using bone graft and implantableprosthetics including plates, rods, and bone engaging fasteners.

It will be understood that various modifications may be made to theembodiments disclosed herein. Therefore, the above description shouldnot be construed as limiting, but merely as exemplification of thevarious embodiments. Those skilled in the art will envision othermodifications within the scope and spirit of the claims appended hereto.

What is claimed is:
 1. A surgical instrument, comprising: an outer shaftextending along a longitudinal axis between a first end of the outershaft and an opposite second end of the outer shaft, the outer shaftcomprising an inner surface defining a passageway; an inner shaftdisposed within the passageway, the inner shaft extending between afirst end of the inner shaft and an opposite second end of the innershaft, the inner shaft comprising an inner surface defining a lumen; anexpandable structure having a first end coupled to the second end of theouter shaft and an opposite second end coupled to the second end of theinner shaft, the expandable structure comprising an inner surfacedefining a chamber, the inner shaft being movably disposed within thepassageway such that moving the inner shaft axially along thelongitudinal axis positions at least a portion of the expandablestructure within the passageway; a delivery shaft comprising a first endpositioned within the passageway and a second end positioned within thechamber, the delivery shaft comprising an inner surface defining achannel configured to deliver a coolant out of an opening in the secondend of the delivery shaft and into the chamber to move the expandablestructure from an unexpanded configuration to an expanded configuration;and a variable exhaust valve in communication with the passagewayconfigured to regulate pressure within the chamber.
 2. The surgicalinstrument as recited in claim 1, further comprising: a pressuremonitor; and a coolant source comprising a supply of the coolant,wherein the pressure monitor is configured to send a signal to thecoolant source to turn a pump of the coolant surface off when pressurewithin the chamber reaches a selected threshold pressure.
 3. Thesurgical instrument as recited in claim 2, wherein the coolant source isin communication with the channel.
 4. The surgical instrument as recitedin claim 2, wherein the pressure monitor comprises a first endpositioned in the passageway and a second end positioned in the chamber.5. The surgical instrument as recited in claim 2, wherein the coolantsource is in communication with the channel.
 6. A surgical methodcomprising: providing the surgical instrument of claim 1; creating anincision; creating a surgical pathway from the incision to cancellousbone; positioning the expandable structure within the cancellous bone;delivering the coolant into the chamber to move the expandable structurefrom the unexpanded configuration to the expanded configuration tocreate a cavity within the cancellous bone; and decreasing pressurewithin the chamber to create cold energy that denervates the cancellousbone.
 7. The method as recited in claim 6, wherein: delivering thecoolant into the chamber comprises increasing pressure within thechamber to a first pressure to create the cavity; decreasing pressurewithin the chamber comprises adjusting pressure within the chamber fromthe first pressure to a second pressure that is less than the firstpressure to create the cold energy; and the first pressure is greaterthan about 50 psi and the second pressure is about 10 psi.
 8. The methodas recited in claim 7, wherein the coolant is maintained within thechamber as pressure within the chamber is decreased.
 9. The method asrecited in claim 6, wherein decreasing pressure within the chambercomprises adjusting the variable exhaust valve.
 10. The method asrecited in claim 6, further comprising: moving the expandable structurefrom the expanded configuration to the unexpanded configuration;removing the surgical instrument from the cavity; and filling the cavitywith bone cement.
 11. A surgical instrument, comprising: an outer shaftdefining a longitudinal axis, the outer shaft comprising an innersurface defining a passageway; an inner shaft movably disposed withinthe passageway, the inner shaft comprising an inner surface defining alumen; a balloon having a first end coupled to the outer shaft and anopposite second end coupled to the inner shaft, the balloon defining achamber; a delivery shaft comprising a first end positioned within thepassageway and a second end positioned within the chamber, the deliveryshaft defining a channel configured to deliver a coolant out of thedelivery shaft and into the chamber to inflate the balloon; and avariable exhaust valve in communication with the passageway configuredto regulate pressure within the chamber, wherein the inner shaft ismovable relative to the outer shaft to move the balloon from a firstorientation in which the balloon is positioned entirely outside of thepassageway and a second orientation in which at least a portion of theexpandable structure within the passageway.
 12. The surgical instrumentas recited in claim 11, further comprising: a pressure monitor; and acoolant source comprising a supply of the coolant, wherein the pressuremonitor is configured to send a signal to the coolant source to turn apump of the coolant surface off when pressure within the chamber reachesa selected threshold pressure, wherein the pressure monitor comprises afirst end positioned in the passageway and a second end positioned inthe chamber, and wherein the coolant source is in communication with thechannel.
 13. A surgical instrument, comprising: an outer shaft defininga longitudinal axis, the outer shaft comprising an inner surfacedefining a passageway; an inner shaft movably disposed within thepassageway, the inner shaft comprising an inner surface defining alumen; a balloon having a first end coupled to the outer shaft and anopposite second end coupled to the inner shaft, the balloon defining achamber; a delivery shaft defining a channel configured to deliver acoolant out of the delivery shaft and into the chamber to inflate theballoon, wherein the inner shaft is movable relative to the outer shaftto move the balloon from a first orientation in which the balloon ispositioned entirely outside of the passageway and a second orientationin which at least a portion of the expandable structure within thepassageway.
 14. The surgical instrument as recited in claim 13, furthercomprising: a pressure monitor; and a coolant source comprising a supplyof the coolant, wherein the pressure monitor is configured to send asignal to the coolant source to turn a pump of the coolant surface offwhen pressure within the chamber reaches a selected threshold pressure,wherein the pressure monitor comprises a first end positioned in thepassageway and a second end positioned in the chamber, and wherein thecoolant source is in communication with the channel.